This cannot be overstated. To wit, a Honda Accord (or equivalent mid-range car of today) is objectively superior to a Rolls Royce from the 90s in terms of amenities, engine power/efficiency, quietness, build quality, safety, etc. The same is true for quality-of-life improvements across a vast swath of consumer goods, and therefore consumer lifestyles.
Without growth, it's unlikely we'd see those improvements manifest. Carefully consider the lifestyle of someone living several decades ago. Would you honestly want to live such a lifestyle yourself? That's where degrowth likely leads. As the article says, "I feel it’s impossible to convince Europeans to act in their self interest. You can’t even convince them to adopt air conditioning in the summer."